<template>
  <div>
    <table border="1" width="700" style="border-collapse: collapse">
      <caption>
        购物车:
        <ul>
          <li v-for="(item, index) in goodList" :key="index">
            {{ item.name }}--{{ item.num }}件
          </li>
        </ul>
        <p>合计:{{ allNum }}</p>
      </caption>
      <thead>
        <tr>
          <th>
            <input type="checkbox" v-model="allSelect" /> <span>全选</span>
          </th>
          <th>名称</th>
          <th>价格</th>
          <th>数量</th>
          <th>总价</th>
          <th>操作</th>
        </tr>
      </thead>
      <tbody>
        <tr v-for="(item, index) in goodList" :key="index">
          <td>
            <input
              type="checkbox"
              v-model="item.checked"
              :value="item.checked"
            />
          </td>
          <td>{{ item.name }}</td>
          <td>{{ item.price }}</td>
          <td>
            <button @click="btnDown(index)">-</button>{{ item.num
            }}<button @click="btnUp(index)">+</button>
          </td>
          <td>{{ item.price * item.num }}</td>
          <td><button @click="del(index)">删除</button></td>
        </tr>
      </tbody>
      <tfoot>
        <tr>
          <td>合计:</td>
          <td colspan="5">{{ allPrice }}</td>
        </tr>
      </tfoot>
    </table>
  </div>
</template>

<script>
export default {
  data() {
    return {
      goodList: [
        {
          name: "诸葛亮",
          price: 1000,
          num: 1,
          checked: false,
        },
        {
          name: "蔡文姬",
          price: 1500,
          num: 1,
          checked: false,
        },
        {
          name: "妲己",
          price: 2000,
          num: 1,
          checked: false,
        },
        {
          name: "鲁班",
          price: 2200,
          num: 1,
          checked: false,
        },
      ],
    };
  },
  methods: {
    btnUp(index) {
      this.goodList[index].num++;
    },
    btnDown(index) {
      this.goodList[index].num =
        this.goodList[index].num < 0 ? this.goodList[index].num-- : 0;
    },
    del(index) {
      this.goodList.splice(index, 1);
    },
  },
  computed: {
    allPrice() {
      return this.goodList.reduce((sum, obj) => {
        if (obj.checked == true) {
          sum += obj.price * obj.num;
        }
        return sum;
      }, 0);
    },
    allNum() {
      return this.goodList.reduce((sum, obj) => (sum += obj.num), 0);
    },
    allSelect: {
      set(val) {
        this.goodList.forEach((obj) => (obj.checked = val));
      },
      get() {
        return this.goodList.every((obj) => obj.checked === true);
      },
    },
  },
};
</script>

<style>
table,
tr,
td {
  text-align: center;
  border: 1px solid black !important;
}
</style>